Ledeburitic, preliminary iron alloy free from graphite



Patented Feb. 20, 1934 LEDEBURITIC, PRELIMINARY IRON ALLOY FREE FROM GRAPHITE Josef Novak and Roman Kesselring, Novy Bohumin, Czechoslovakia No Drawing. Application April 12, 1932, Serial No. 604,868, and in Germany April 13, 1931 3 Claims. (01. 75-1) The invention in our co-pending application 553681/31, now Patent No. 1,890,540, Dec. 13, 1932, comprises a ledeburitic iron pre-alloy free from graphite, characterized by a chromium con- 5 tent of 20 to 30%, a tungsten content of 5 to 6%,

a nickel content of 6 to 10%, a copper content of 10 to 15% and a carbon content of 2% to 3%.

This pre-alloy serves, in the first instant for manufacturing a steel practically free from silil con, that is not over 0.002% and containing chromium 0.1 to 1%, copper 0.25 to 0.50%, nickel 0.04 to 0.25% and tungsten 0.01 to 0.05%.

For the production of steels, which are to contain, besides the above-enumerated metals, chromium, tungsten, nickel and copper, also refining metals, such as zirconium, aluminium, boron, beryllium, molybdenum and titanium singly or in combination, pre-alloys are to be used, which contain both of said groups of metals. Alloys of this character are the object of the present invention.

I All these pre-alloys contain iron and the refining metals within the following limits namely: chromium 20 to 30%, tungsten 2 to 6%, nickel 6 to 15% and copper 10 to 15%, together with 2 to 3% carbon, which is presentas a carbide combination. The alloys are, consequently, all free from graphite and have a ledeburitic structure.

Besides these components, contained in common with the pre-alloy according to the copending application No. 553681. now Patent No. 1,890,540, Dec. 13, 1932, the pre-alloy of the present invention contains also the following refining metals: about 5 to 8% zirconium, 2 to 3% aluminium, 3 to 4% boron, 8 to 10% beryllium, 5 to 18% molybdenum and 1 to 2% titanium.

The refining metals last named may be con- 40 tained in the present pre-alloy singly or in combination.

Below are stated four modifications of the prealloy according to the present invention by way of example, which have proved highly satis- Fe remainder Example II Per cent Cr 20-30 Cu 10-15 Ni 6-10 Be 8-10 Mo 5-10 Al 2-3 C 2 -3 Fe remainder Example I II Per cent Cr 20-25 Cu 10-15 Ni 6-10 Mo 10-12 C 2 /g3 Fe remainder Example IV Per cent Cu 10-15 M 6-15 W 5-6 Mo 15-18 A1 2-3 Ti a 1-2 C 2 -3 Fe remainder nickel and partially refined copper or CODIJBT- aluminum respectively. Addedto this are, as the case may be, the required quantity of the further refining metals:

zirconium, aluminum, boron,

beryllium, molybdenum and titanium. The mixture is then thoroughly melted in a covered and strongly heated crucible of graphite, the slag layer is then removed, and the melt is, if necessary. well stirred and then cast in moist sand in simple moulds-and is made to solidify as quickly as possible'. In this Way are obtained the alloys of a ledeburitic structure, in which now also bon is present as a carbide-combination the alloys are free from graphite.

the carso that The pre-alloys serve, in the first line, for producing steels practically free from silicon. By using the new alloys as a pre-alloy for manufacturing special steels practically free from silicon, the valuable advantage is obtained that it becomes possible to add to the steel also the highly combustible refining metals: zirconium, aluminum, boron, beryllium, molybdenum and titanium, without causing any losses. The substance composition of the finished steel is not within the scope of the invention.

We claim:

I. A ledeburitic pre-alloy free from graphite for manufacturing steels containing carbon, chromium, tungsten, nickel, copper and iron, said prealloy containing approximately the following main constituents: 20 to 30% chromium, 2 to 6% tungsten, 6 to 15% nickel, 10 to 15% copper", 2% to 3% carbon; and of auxiliary constituents consisting of 5 to 18% molybdenum and the balance substantially iron and impurities.-

2. A pre-alloy free from graphite intended for use in the manufacture of steels containing carbon, chromium, tungsten, nickel, copper and iron, said pre-alloy containing approximately the following main constituents: 20 to 30% chromium, 10 to 15% copper, 6 to 10% nickel, 2 to 3% tungsten and 2 to 3% carbon; and auxiliary constituents consisting of 5 to 8% zirconium and 6 to 12% molybdenum and the balance substantially iron.

6. A pre-alloy free from graphite intended for use in the manufacture of steels containing carbon, chromium, tungsten, nickel, copper and iron, said pre-alloy containing approximately the fol lowing main constituents: -20 to 30% chromium, 10 to 15% copper, 6 to 10% nickel, 2 to 3% tun'g sten and 2 to 3% carbon; and auxiliary fdonstituents consisting of 15 to 18% molybdenunifand 1 to 2% titanium and the balance substantially iron.

JOSEPH NOVAK; V ROMAN KESSELRING.

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